Pig Vaginal Bleeding: Causes, Heat Cycle Clues & Emergency Signs

Not every red stain near the rear end is true vaginal bleeding. In pigs, pet parents may notice blood from the vulva, blood mixed with urine, or discharge stuck to the skin. Your vet will want to sort out where it is coming from first, because the causes and urgency can be very different.

One possible explanation is the heat cycle. Female pigs in estrus may show vulvar swelling, mounting behavior, vocalizing, restlessness, and sometimes a small amount of vaginal discharge. Merck notes that vulvar swelling and discharge can occur around estrus, especially in gilts, but these physical signs are not always reliable on their own. A light smear of pink-tinged mucus may be seen in some pigs, but obvious bleeding should still prompt a call to your vet.

A more serious cause is uterine disease, especially after farrowing. Merck describes metritis in sows as a white to brown, often foul-smelling discharge that may contain tissue or fetal membrane material within 48 hours after farrowing. These pigs may also have fever, poor appetite, sepsis, mastitis, or reduced milk production. In a pet pig, any bloody, brown, or bad-smelling discharge after giving birth is a same-day veterinary issue.

Blood near the vulva can also come from the urinary tract. Merck reports that pigs with cystitis or pyelonephritis may show hematuria, pyuria, anorexia, and foul-smelling urine, and the discharge may not line up with the heat cycle. Trauma, bite wounds, breeding injury, foreign material, reproductive tract infection, toxin-related vulvar irritation such as zearalenone exposure, or pregnancy loss can also cause bleeding or blood-tinged discharge.

See your vet immediately if the bleeding is more than a light smear, keeps recurring, or is paired with weakness, pale gums, collapse, straining, pain, fever, vomiting, or a bad odor. This is especially important if your pig is pregnant, recently farrowed, may have been bred, or is acting dull and not eating. Bloody discharge after farrowing can point to metritis or retained material, and blood in the urine can signal urinary tract disease that needs prompt care.

A same-day visit is also wise if you are not sure whether the blood is coming from the vulva or the urine. Pigs can hide illness well. By the time appetite drops or they isolate themselves, the problem may be more advanced than it looks.

You may be able to monitor briefly at home only if your pig is bright, eating normally, passing urine and stool comfortably, and you saw a tiny amount of pink-tinged mucus during an otherwise typical heat cycle with no odor, no pain, and no repeat bleeding. Even then, take photos, note the date, and track behavior. If the discharge becomes redder, heavier, foul-smelling, or lasts more than a day, contact your vet.

When in doubt, err on the side of an exam. Merck's general guidance for animals includes bleeding from the urinary or genital area as a reason for veterinary attention.

Your vet will start with a history and physical exam. Expect questions about age, spay status if applicable, recent heat signs, breeding exposure, pregnancy or farrowing history, appetite, urination, stool, and whether the discharge has an odor or contains tissue. Photos of the bleeding and the bedding can be very helpful.

The first goal is to localize the source. Your vet may examine the vulva and surrounding skin, check for trauma, and look for signs that the blood is actually in the urine. Depending on the case, diagnostics may include a urinalysis, bloodwork, vaginal or discharge cytology, culture, ultrasound, or radiographs. Ultrasound is often useful when your vet is concerned about uterine fluid, retained material, pregnancy complications, bladder disease, or masses.

Treatment depends on the cause. A pig in heat with mild discharge may only need monitoring and follow-up. A pig with urinary disease may need urine testing, pain control, and targeted treatment. A pig with suspected metritis, sepsis, or significant blood loss may need systemic medications, fluids, and close monitoring. If there is severe trauma, retained fetal material, a uterine emergency, or uncontrolled bleeding, referral, sedation, or surgery may be discussed.

Because pigs vary widely in size and handling needs, your vet may also talk with you about safe transport, sedation risk, and whether farm-call or clinic care makes the most sense.

Home care is supportive, not a substitute for veterinary guidance when bleeding is present. Keep your pig in a clean, dry, quiet area with easy access to water and familiar food. Replace soiled bedding often so you can monitor the amount and color of any discharge. If possible, separate from rough pen mates that may mount, bump, or worsen irritation.

Do not give human pain relievers, hormones, leftover antibiotics, or over-the-counter creams unless your vet specifically tells you to. These can make diagnosis harder and may be unsafe for pigs. Avoid repeated cleaning inside the vulva. If the skin around the rear end is dirty, gently clean the outside only with warm water and pat dry.

Track appetite, water intake, urination, stool, temperature if your vet has shown you how, and any signs of straining or discomfort. Take clear photos of the discharge on the pig and bedding. Note whether the pig is cycling, recently bred, pregnant, or recently farrowed. This timeline can help your vet narrow the cause quickly.

If bleeding increases, the discharge smells bad, your pig becomes lethargic, stops eating, strains to urinate, or seems painful, move from monitoring to urgent veterinary care right away.